ArticlePDF Available

Physical Chemical Properties of Fermented and Roasted Rambutan Seed Fat (RSF) as A Potential Source of Cocoa Butter Replacer

Authors:

Abstract and Figures

Rambutan (Nephelium opossum L) is one of the most important tropical fruits that is originally found in Malaysia, Thailand, the Philippines, Vietnam, Borneo and other countries in this region. The industrial processing of this fruit produces seeds and peels as waste materials. The aim of this work was to determine the physical-chemical properties of fermented-roasted Rambutan seed fat (RSF) and its mixtures with Cocoa butter (CB) in term of viscosity, texture (hardness), thermal stability, and fatty acid composition, and free fatty acid, acid value. The mixtures M3, M4, and RSF which possess similar crystal formation showed almost similar hardness index in the range of 11.18 to 24.77. The mixtures M1 and CB exhibited higher hardness index than M2, M3, M4 and RSF in the range of 57.55 to 63.85. The results showed that a low viscosity was observed in the mixture CB and M1 with increasing the temperatures at 35, 40 and 50 oC whereas, a high viscosity was observed in the other mixture such as M3, M4, and RSF with increasing the temperature, respectively. The result found that the major fatty acid composition was present in CB (100%CB+0%RSF) and M1 (80%CB+20%RSF), such as palmitic, stearic and oleic acid, respectively. The results showed no significant differences (P > 0.05) in FFA among CB (2.72±0.65%), M1 (3.01±0.32%) and M2 (3.47±0.16%). At the same time, the results of A.V showed significant differences (P < 0.05) among CB (4.68±1.29), M1 (5.98±0.64) and M2 (6.92±0.33) mgKOH/g, respectively, but M1 value was very close to CB value. The results exhibited that CB and M1 had a lower viscosity than M2, M3, M4 and RSF with increasing temperature. From these results, it was found that it is possible to utilize rambutan seed fat as a cocoa butter replacer in a suitable ratio depending on the final products.
Content may be subject to copyright.
Vol.
7
(201
7
) No.
1
ISSN: 2088
5334
Physical Chemical Properties of Fermented and Roasted Rambutan
Seed Fat (RSF) as A Potential Source of Cocoa Butter Replacer
Luma Khairy.H#,*, Fered Saadoon#,%, Boshra Varastegani#, Tajul A. Yang#, Wahidu Zzaman#,&
#Food Technology, School of Industrial Technology, University Sains Malaysia, Minden 11800 Pulau Pinang Malaysia
E-mail: taris@usm.my
*Department of Food Science, School of Agriculture, University of Baghdad, Baghdad- Iraq
Email: luma_khairy@yahoo.com
%Department of Quality control, General Company for Grain Processing, Ministry of trade, Baghdad, Iraq
E-mail: feredabuaimen@yahoo.com
&Department of Food Engineering and Tea Technology, Shahjalal University of Science and Technology, Sylhet-3114, Bangladesh
Corresponding author Email: wahidaft@yahoo.com
Abstract Rambutan (Nephelium opossum L) is one of the most important tropical fruits that is originally found in Malaysia,
Thailand, the Philippines, Vietnam, Borneo and other countries in this region. The industrial processing of this fruit produces seeds
and peels as waste materials. The aim of this work was to determine the physical-chemical properties of fermented-roasted Rambutan
seed fat (RSF) and its mixtures with Cocoa butter (CB) in term of viscosity, texture (hardness), thermal stability, and fatty acid
composition, and free fatty acid, acid value. The mixtures M3, M4, and RSF which possess similar crystal formation showed almost
similar hardness index in the range of 11.18 to 24.77. The mixtures M1 and CB exhibited higher hardness index than M2, M3, M4 and
RSF in the range of 57.55 to 63.85. The results showed that a low viscosity was observed in the mixture CB and M1 with increasing
the temperatures at 35, 40 and 50 oC whereas, a high viscosity was observed in the other mixture such as M3, M4, and RSF with
increasing the temperature, respectively. The result found that the major fatty acid composition was present in CB
(100%CB+0%RSF) and M1 (80%CB+20%RSF), such as palmitic, stearic and oleic acid, respectively. The results showed no
significant differences (P > 0.05) in FFA among CB (2.72±0.65%), M1 (3.01±0.32%) and M2 (3.47±0.16%). At the same time, the
results of A.V showed significant differences (P < 0.05) among CB (4.68±1.29), M1 (5.98±0.64) and M2 (6.92±0.33) mgKOH/g,
respectively, but M1 value was very close to CB value. The results exhibited that CB and M1 had a lower viscosity than M2, M3, M4
and RSF with increasing temperature. From these results, it was found that it is possible to utilize rambutan seed fat as a cocoa butter
replacer in a suitable ratio depending on the final products.
Keywords rambutan seed; cocoa butter; texture; thermal stability; fatty acid composition
I. INTRODUCTION
Fats are used as main ingredients in food, cosmetic, and
pharmaceutical products [1]. The crystallization of fats has
industrial applications when it is controlled; end products
such as chocolate, margarine, and whipped cream can be
obtained; the crystallization phenomenon of fats can be used
to isolate fats from natural resources [2]. Cocoa butter (CB)
is one of the natural fats, obtained from cocoa seeds
(Theobroma cacao); it is typically used as a major
component of chocolate and other confectionery products
because of its physical and chemical properties [3]. CB is
solid at room temperature (below 25 °C) and liquid at body
temperature (~37 °C); it consists mostly of palmitic (C16),
stearic (C18:0), and oleic acids. Virtually, all oleic acids are
esterified in the central position of all glycerol molecules
(Sn-2), whereas saturated fatty acids are typically located in
(Sn-1,3) positions. The composition and allocation of fatty
acids lead to a symmetrical triglyceride composition of CB
that is rich in 1,3-dipalmitoyl1-2-oleoyl-glycerol (pop) and
1-palmitoyl-3-stearoyl-2-oleoyl-glycerol (POS) [4]. This
triglyceride composition of CB is generally responsible for
its diverse crystalline polymorphic forms, while fatty acid
compositions are responsible for fat solidification in its
liquid state [5]. CB is known to be more expensive than
other vegetable fats because of its specific characteristics
57
and it is cultivated in only a few countries [6]. Therefore,
the food industry is keen to find other sources of fats as
alternatives to CB in producing chocolates for various
reasons, including economic [7]. CB alternatives are defined
as non-lauric fats that can replace CB either partially or
completely in chocolate or other food products. Lipp and
Anklam [8] previously mentioned that the utilization of
natural or processed lipids as cocoa butter alternative can be
decided using its compositional data (fatty acid composition
and triacylglycerol conformation) and thermal characteristics
such as crystallization and melting characteristic. This work
was intended to determine the physical properties of
fermented-roasted RSF and its mixtures with CB in viscosity,
texture (hardness), thermal stability, fatty acid composition,
free fatty acid, acid value to compare these mixtures with
CB and to determine the mixture which was more similar to
cocoa butter properties.
II. MATERIALS AND METHODS
A. Materials
CB was purchased from an Indonesian coffee company
and the Cocoa Research Institute, Jember, East Java,
Indonesia. Meanwhile, raw rambutan (Nepheliumlappaceum
L.) seeds were supplied by a rambutan canning industry in
Sungai Petani, Kedah, Malaysia.
B. Fermentation and Roasting of Rambutan Seeds
The fermentation process was performed on rambutan
seeds, which were still covered by small amounts of
rambutan pulp. The rambutan seeds were transferred into
plastic baskets (625 mm × 425 mm × 294 mm), which were
previously lined with banana leaves. After filling in the
baskets with raw rambutan seeds, the baskets were covered
with banana leaves for 6 days, with mixing every 3 days. On
the 6th day of fermentation, the banana leaves cover was
opened and the rambutan seeds inside the fermentation
container were stirred with a wood spatula. After the
fermentation time was sufficient, the dried rambutan seeds
were roasted at 150 °C for 30 minutes by oven-drying
(AFOS Mini Kiln, Hull, England). After roasting, the
samples were cooled at room temperature and stored until
the screw-pressing process for RSF production [9].
C. RSF Extraction
RSF extraction was performed using a KOMET screw oil
expeller DD 85 IG (IBG MonfortsOekotec GmbH & Co. KG,
Ger-many). Dried rambutan seeds were dehusked and heated
at 60 °C for 30 minutes by oven-drying (AFOS Mini Kiln,
Hull, England). The screw-pressing process produced RSF,
which was a viscous mixture of rambutan seed powder and
RSF. The separation of RSF from rambutan seed butter was
achieved through filtration under a heated condition (60 °C).
Afterward, the collected RSF was transferred into inert-
screw-cap bottles [9].
D. Preparation of RSF and Cocoa Butter Mixtures
Mixtures of rambutan seed fat and cocoa butter were
prepared following proportions as mentioned in Table 3.1.
The levels were in the range of 0% to 100% with the total
mixture was 100% (CB+RSF=1). The mixing process was
carried out by adding predetermined proportions (w/w) of
cocoa butter and rambutan seed fat.
TABLE I
PROPORTION OF THE RSF AND COCOA BUTTER
Mixtures of CB & RSF CB%
a
RSF%
b
Mixture 1 (CB) 100 0
Mixture 2 (M1) 80 20
Mixture 3 (M2) 60 40
Mixture 4 (M3) 40 60
Mixture 5 (M4) 20 80
Mixture 6 (RSF) 0 100
a CB% = proportion of cocoa butter, b RSF% = proportion of Rambutan seed
fat
CB was incorporated into RSF in six proportions, namely,
100/0, 80/20, 60/40, 40/60, 20/80, and 0/100 (w/w) CB to
RSF, as CB, M1, M2, M3, M4 and RSF respectively. Then,
the mixtures were melted in the oven (AFOS Mini Kiln, Hull,
England) at 60 °C for 15–20 minutes. The melted mixtures
were then homogenized using a vortex and transferred into
inert-screw-cap bottles and then stored at −4 °C until they
were used for analysis.
E. Texture Properties (Hardness Index)
Texture properties analysis was carried out using TA.XT
Plus texture analyzer (Stable Micro System, Ltd., UK)
following the method of Lannes et al. [10]. Cone probe was
utilized during this analysis and was set to penetrate the
samples with a constant speed of 2.0 mm/s for 10.0 mm. The
analysis was performed at 20˚C. The result of the analysis
was expressed as hardness diagram.
F. Thermal Stability Analysis
Thermal stability of RSF and CB mixture samples were
analyzed by means of thermal gravimetric analysis (TGA) in
nitrogen atmospheres employed TGA 4000 equipped with
C6 cooler (Perkin Elmer, Waltham, Massachusetts, USA).
The nitrogen flow rate was set at 50 ml/min at a heating rate
of 20˚C/min. Mass changes were recorded between 25 until
700 ˚C.
G. Viscosity Measurement
The viscosity was measured by use Viscometer Model
(SV-10 Japan). It was taken 45 ml of the sample and
transfers to Viscometer vial and then read the number of the
viscosity. Each value was taken triplicate at temperature 25
oC.
H. Fatty Acid Composition
Fatty acid methyl ester (FAME) was prepared according
to the method of Mondello et al. [11]. Melted samples (0.05
g) were transesterified in a Pyrex tube by using 2 ml of
borontrifluoride-methanol (20:80) reagent then heated for 30
min at 100°C in water bath. The heated solution was cooled
to room temperature. After cooling down, 2 ml of n-hexane
and 8 ml of distilled water were added to the mixture, which
was then mixed manually for 1 min and centrifuged at 3500
rpm for 2 minutes. Approximately 1 ml of the upper n-
hexane layer was transferred to a 1.5 ml glass insert for 2 ml
vials after diluting the extracted hexane to obtain a suitable
chromatographic response. Gas Chromatography (GC)
58
analysis was done using GC 2010 plus- FID (flame
ionization detector) (Shimadzu Corp., Nagakyo-ku, Kyoto,
Japan) equipped with SGE BPX70 (90% Cyanopropylphenyl
Polisiloxane, 0.32mm ID × 0.25μm × 30m) column (SGE
Analytical Science Pty Ltd, Victoria, Australia). The
condition of GC during the analysis was set as follows: The
injection port was set using split mode (split ratio = 1:10) at
temperature 250oC employed Helium (He) as carrier gas [11].
The column temperature was set at 70oC maintained for 1
min, then increasing to 150oC at 20o C/min ramp and then
increasing to 250oC at 10o C/min ramp. The final
temperature was maintained for 15 min. Fatty acids were
grouped as follows: saturated (SFA), mono (MUNA) and
poly (PUFA) fatty acids.
I. Analysis of Free Fatty Acid (FFA) and Acid Value (A.V)
The FFA was determined according to the method [12].
The first step was prepared 50 ml of alcohol by added in 2
ml phenolphthalein solution and 0.1 M sodium hydroxide
(NaOH) and produced a faint permanent pink. 7.05 grams of
melted fat sample were weighed into 250 ml conical flask
and mixed with prepared neutralized 50 ml of alcohol at first
step. Then, the mixture was titrated with 0.25 M sodium
hydroxide (NaOH) with a vigorous shaking until a
permanent faint pink developed. The volume of 0.25 sodium
hydroxide (NaOH) used in the titration steps was taken as
final read. The free fatty acid of the samples was expressed
as a percentage of oleic acid that was ml of 0.25 M sodium
hydroxide (NaOH) used in the titration of the sample. All
samples were measured in triplicate. The acid value of RSF
and its mixture with CB samples are correlated with free
fatty acid determination. FFA may also be expressed in
terms of acid value. The acid value of the samples was
calculated by the equation below:
A.V= percentage of fatty acid (as oleic) × 1.99 (1)
J. Statistical Analysis
Samples were carried out in triplicate and the data
analysis was using (ANOVA) followed by post hoc analysis,
Duncan multiple comparison analysis and all the data were
analysis using SPSS (Statistical Package for Social Science)
software version 20 (IBM Corporation, Armonk, New York
10504-1722 United State). The statistical analysis was
performed at 0.05 significant levels.
III. RESULTS AND DISCUSSION
A. Texture Properties (Hardness Index)
The differences in crystal formation of the mixtures
greatly affected their texture properties. As shown in Fig. 1,
the mixtures M3, M4 and RSF which possess similar crystal
formation showed almost similar hardness index in the range
of 11.18 to 24.77. The mixtures M1 and CB exhibited higher
hardness index than M2, M3, M4 and RSF in the range of
57.55 to 63.85. These results were agreed with Febrianto [9],
he found the hardness of the mixtures (RSF: CB) were lower
ranged from 21.32 to 27.91 compared to 56.34 in CB.
However, he showed a slightly different characteristic of
hardness in the mixture (90%CB/10%RSF) compared to
cocoa butter. Size and the distribution of crystal formation
may be the responsible factor for the difference between M2,
M3, M4 and RSF mixtures with M1 and CB. Smaller and
well-distributed crystal formation provides a higher hardness
index, whereas bigger crystal formation resulted otherwise.
Fig. 1 Changes in the hardness index of RSF and its mixtures with CB
B. Thermal Stability
The result of thermal stability analyses carried out on RSF
and its mixture with CB are shown in Table 2. The
decomposition temperature of M1 was more similar to CB, it
was observed in onset 344.39 and 394.59, mass loss rate
1.38 and 0.79, and the final decomposition temperature
521.14 and 616.06 of the M1 and CB, respectively. This
result indicated that CB and M1 were more resistant from
thermal decomposition than other mixtures. However, the
other mixtures showed different results; decomposition of
M2, M3, M4, and RSF started at 308.62, 306.75, 302.60 and
291.91, and ended at a lower temperature ranged around
489.89, 487.52, 485.85 and 482.83 than that of the CB and
M1 with the highest mass loss recorded at around 1.25 to
1.12%/˚C, respectively.
Previously, Lawler and Dimick [13] showed that cocoa
butter possessed the unique characteristic of polymorphism.
As mentioned in section 3.3.3; CB and M1 crystallized as β
form crystal, The β crystal formation possesses hard, but the
brittle texture of cocoa butter which is usually used for
storage and product development. This formation of the
crystal is also desirable due to its unique snap characteristic
and fast melting in the mouth feature. Therefore, CB and M1
were more resistant from thermal decomposition than the
mixture M2, M3, M4 and RSF, which crystallized in β and β'
form crystal. Nonetheless, similar to the thermal behavior
discussed in section 3.3.2; different thermal stability of RSF
compared to the CB may be also contributed by the TAG
composition.
C. Viscosity Measurement
The changes in physical properties of rambutan seed fat
and its mixture with cocoa butter during the roasting process
are considered a reliable guide to follow up the changes in
viscosity affected by different temperature.
59
TABLE II
TGA DEGRADATION POINT OF RSF AND ITS MIXTURE WITH CB
Sample
Degradation point (°C)
Onset
Max 1
Mass
loss
rate 1
(%/°C)
Max 2
Mass
loss
rate 2
(%/°C)
Offset
CB 394.59 431.69 0.22 522.12 0.79 616.06
M1 344.39 391.66 0.81 482.66 1.38 521.14
M2 308.62 338.53 0.87 432.92 1.25 489.89
M3 306.75 311.66 0.64 430.68 0.98 487.52
M4 302.60 307.96 0.71 429.53 1.12 485.85
RSF 291.91 306.39 0.52 425.01 1.12 482.83
The results of viscosity measurement are given in Fig. 2.
The results showed that a low viscosity was observed in the
mixture CB and M1 with increasing the temperatures at 35,
40 and 50 oC. whereas, a high viscosity was observed in the
other mixture such as M3, M4, and RSF with increasing the
temperature, respectively.4
Fig. 2 Changes in viscosity of RSF and its mixtures with CB at different
temperature
These results correspond with Zzaman et al. [14], he
suggested that mixture proportion up to 30% rambutan seed
fat had a higher viscosity than cocoa butter. Accordingly,
cocoa butter had a lower viscosity than rambutan seed fat,
which can be explained by type and long chain structure of
fatty acid and triacylglycerol composition [15]. According to
Lannes et al. [16] noted that characterized by the melting of
fat crystals is defined as the level of fat in a reticular
structure which are typically structured in the form of β’ that
conducted lead to higher viscosity more than β form
structure that given their smaller size, higher surface area
and potentially increased interfacial viscosity in emulsions.
D. Fatty Acid Composition
Cocoa butter contains many different lipids or fats.
According to Lannes and Gioielli [17] described that
primary triacylglycerols that combined with the cocoa butter
including; palmitic, stearic, and oleic fatty acids. Saturated
and unsaturated acids are obtained from many fats and lipids
combination of the fatty acids, which half of them are
heterogeneous. The fatty acid composition of all mixtures
was significantly different (p < 0.05) from one another as
shown in Table 3.
TABLE III
FATTY ACID COMPOSITION (% AREA) IN THE CB AND RSF MIXTURE
Fatty
acid
M1 M2 M3 M4
C8:0
1.13±0.02 1.27±0.01
1.41±0.01 1.55±0.01
C11:0
0.15±0.01
0.30±0.01
0.46±0.01 0.61±0.01
C12:0
15.69±0.01
12.38±0.01 9.08±0.01
5.77±0.01
C13:0
0.88±0.01
1,76±0.01
2.65±0.01
3.53±0.01
C14:0
0.63±0.01 1.25±0.02 1.87±0.01
2.51±0.01
C15:0 0.82±0.01 1.65±0.01
2.47±0.01
3.31±0.01
C16:0
22.14±0.01
18.55±0.01
14.97±0.01
11.38±0.01
C
16:1
2.65±0.01
5.31±0.01
7.94±0.01
10.59±0.01
C18:0 18.05±0.01
15.56±0.01
13.08±0.01
10.57±0.02
C18:1
cis 23.06±0.01
23.68±0.01
23.96±0.01
24.91±0.01
C18:1
trans 0.74±0.01
1.47±0.01
2.21±0.01
2.94±0.01
C18:2
trans 3.54±0.01
2.65±0.01
1.77±0.01
0.88±0.01
C18:3
2.72±0.01
2.54±0.01
2.38±0.01
2.21±0.01
C20:0
3.11±0.01
6.21±0.01
9.34±0.01
12.45±0.01
C20:1
0.65±0.01
1.31±0.01
1.94±0.01
2.58±0.01
C22:0
0.27±0.01 0.54±0.01 0.82±0.01
1.08±0.01
SFA 63.52 60.78 58.09 55.34
MUFA 26.45 30.46 34.11 38.44
PUFA 6.26 5.19 4.15 3.09
-GC analysis and expressed as % area.
-Different superscript letter on the same row represented
significantly different value (p<0.05).
The result found that the major fatty acid composition was
present in CB (100%CB+0%RSF) and M1
(80%CB+20%RSF), such as palmitic, stearic and oleic acid,
respectively. Whereas, two main fatty acid composition was
found in RSF, such as oleic and arachidic acid, add up to
almost 75%; present also are palmitic, stearic, gondoic,
palmitoleic, and behenic acids. The Palmitic acid in the RSF
was present in much smaller amounts (7.81%) than CB and
M1 (25.72%  22.14%); and stearic acid in RSF also showed
like a palmitic acid (8.11%, 20.53% and 18.05%),
respectively. The results showed that the oleic acid was
found in CB and M1 (22.44% and 23.06%) lower than RSF
(25.53%), respectively. The lauric acid content in CB and
M1 (18.99% and 15.69%) was higher than RSF (2.47%).
Moreover; Arachidic acid and other saturated fatty acid such
as gondoic and behenic acid found in RSF, but those fatty
acids were absent in cocoa butter, which may affect to high
melting point and high viscosity of rambutan seed fat [18]-
[19]. However, around 50% of the fatty acids in RSF is
saturated, including a high percentage of arachidic acid, a
fatty acid with a long chain and a relatively high melting
point. This composition gives RSF characteristic
physicochemical properties, thermal and phase behavior.
These results agree with Zzaman et al. [14] they founded
that lauric, palmitic, and stearic fatty acid in rambutan seed
fat were less than cocoa butter, but oleic acid found almost
the same. On the other hand, these results are quite different
compared with Sirisompong et al. [20] reported that RSF is
composed of 36.79% of oleic acid, 34.32% arachidic acid
and 4.69% palmitic acid. However, the differences in these
fatty acid proportions have also been reported previously; in
which, the differences in cultivar and plantation area was
suspected to be the most influencing factors. The increase of
60
oleic acid in CB and RSF sample during fermentation was
previously mentioned by Teng et al. [21], who found that the
increase of lipase activity during fermentation using
Rhizopus spp resulted the formation of oleic acid.
Meanwhile, the specific microorganism such as R.
oligosporus could utilize the fatty acids in lipid body, mainly
palmitic and stearic acid to support their cell wall
phospholipid development, resulting in the decrease of
palmitic and stearic acid in RSF. Moreover,
Sudaryatiningsih and Supyani [22] mentioned that PUFA
such as linoleic and linolenic acid could be generated by
converting oleic acid with desaturase enzymes.
E. Analysis of Free Fatty Acid (FFA) and Acid Value (A.V)
The free fatty acid (FFA) and acid value (A.V) in cocoa
butter and the mixtures with rambutan seed fat under study
were in (Table 4). The results showed no significant
differences (P > 0.05) in FFA among CB (2.72±0.65%), M1
(3.01±0.32%) and M2 (3.40.16%). At the same time, the
results of A.V showed significant differences (P < 0.05)
among CB (4.68±1.29), M1 (5.98±0.64) and M2 (6.92±0.33)
mgKOH/g, respectively, but M1 value was very close to CB
value.
TABLE IIV
ANALYSIS OF FREE FATTY ACID AND ACID VALUE IN RSF
Samples FFA
(% oleic acid) A.V
(mgKOH/g)
CB
(100%CB+0%RSF) 2.72±0.65c 4.68±1.29d
M1
(80%CB+20%RSF) 3.01±0.32c 5.98±0.64cd
M2
(60%CB+40%RSF) 3.47±0.16c 6.92±0.33c
M3
(40%CB+60%RSF) 4.89±0.81b 9.73±1.61b
M4
(20%CB+80%RSF) 6.49±0.00a 12.91±0.00a
RSF
(0%CB+100%RSF) 6.86±0.16a 13.66±0.23a
-Values are mean ± standard deviation of three replications.
-Different superscript letter on the same row represented
significantly different value (p<0.05).
These differences in free fatty acid and acid value
between CB, M1, and M2 were small, some sample had a
higher content, others had a lower content of Diacylglycerols
(DAGs). Diacylglycerols are important because they retard
the phase transformation from β to β, this can negatively
influence the cooling curve and thus be a disadvantage for
the tempering of chocolates. These values are comparable to
those reported by Zaidul et al. [23] who obtained free fatty
acid and acid value during incorporated Palm kernel oil with
cocoa butter, they found most of the blend similar values to
that of cocoa butter. On the other hand, Manaf et al. [24]
found that the FFA values of rambutan seed fat and cocoa
butter they studied were 6.1±2.33% and 1.44±0.42%,
respectively. The presence of the FFA content of the cocoa
butter due to the use of beans from diseased pods or
hydrolysis by lipase from mold contamination. These molds
can be present due to insufficient drying, extended
fermentation or prolonged storage of the beans [25]. In
addition, the increase in FFA and A.V values in the roasted
seed fat could be contributed by hydrolysis of triacylglycerol
during roasting process which produces free fatty acids with
diacylglycerol. Another cause can be too quick drying of the
beans, leading to lack or inadequate loss of volatile acids,
but also hydrolysis occurring during storage can lead to FFA
formation [26].
The free fatty acid liberated from triglycerides in the other
mixtures, such as M3 (4.89±0.81%), M4 (6.49±0.00%) and
RSF (6.86±0.16%) were higher as compared to CB
(2.72±0.65%), M1 (3.01±0.32%) and M2 (3.47±0.16%) (Fig.
3). The variation of the free fatty acid due to differences in
the proportion of the mixture's component of cocoa butter
and rambutan seed fat. The result showed that rambutan
seed fat contains a higher proportion of oleic acid than that
observed in cocoa butter. Therefore, we can exhibit that M3,
M4 and RSF had the highest ratio of rambutan seed fat and
free fatty acid, respectively.
Fig. 3 Analysis of free fatty acid (FFA) of RSF and its mixture with CB
Fig. 4 Analysis of acid value (A.V) of RSF and its mixture with CB
With regard acid value (Fig. 4), high acid value was found
in sample RSF (13.66±0.23) and M4 (12.91±0.00) followed
by M3 (9.73±1.6) and M2 (5.98±0.64) mgKOH/g, whereas a
low acid value was found in the samples CB (4.68±1.29) and
M1 (5.98±0.64) mgKOH/g, respectively. From our results,
the proportion of monounsaturated fatty acid (MUFA) in
rambutan seed fat was (42.46%) significantly higher than
found in cocoa butter (22.44%). That can be explained the
61
highest value of the acid value in rambutan seed fat in
comparison with cocoa butter.
IV. CONCLUSIONS
Our analysis on texture properties, thermal stability, and
viscosity of the mixtures between fermented-roasted
rambutan seed fat and cocoa butter resulted in a conclusion
that the incorporation between RSF and CB may potentially
be applied. The hardnesses of the mixtures were lower
ranged from 11.18 to 24.77 in M3, M4 and RSF compared to
57.55 to 63.85 in M1 and CB. The thermal stability of
fermented-roasted RSF was lower than M1 and CB. The
degradation point exhibited in M1 ranged from 344.39-
521.14˚C and 394.59-616.06 in CB compared to 291.91-
482.83 in RSF. Effect of different temperature on the
viscosity of CB and M1 shows significant differences in
comparison with other mixtures. The results exhibited that
CB and M1 had a lower viscosity than M2, M3, M4 and RSF
with increasing temperature. From these results, it was found
that it is possible to utilize rambutan seed fat as a cocoa
butter replacer which allows the mixing with cocoa butter in
small ratio or can also be utilized for other confectionery
product in the absence of cocoa butter.
ACKNOWLEDGMENT
We extend our appreciation to the school of Industrial
Technology, Department of Food Technology, University
Sains Malaysia for funding the work and their keen interest
in accomplishing this work.
REFERENCES
[1] Gunstone, F. D., and F. B. Padley, Lipid technologies and
applications, 3rd ed., Boca Raton, FL: CRC press, 1997.
[2] Sato, K., “Crystallization behavior of fats and lipids—a review”,
CHEM ENG SCI, 56(7): 2255-2265, 2001.
[3] Shukla, V., and C. Akoh, “Cocoa butter, cocoa butter equivalents,
and cocoa butter substitutes”, Handbook of functional lipids p. 279-
307, 2006.
[4] Bootello, M. A., et al., “Evaluation of high oleic-high stearic
sunflower hard stearins for cocoa butter equivalent formulation”,
FOOD CHEM, 134: 1409-1417, 2012.
[5] Issara, U., W. Zzaman, and T.A. Yang, “Review on Rambutan Seed
Fat as a potential source of cocoa butter substitute in Confectionary
Product”, INT FOOD RES J, 21(1): 25-31, 2014.
[6] Hassan, M., J.B. Philippe, P. Alain, G. Gerard, “Production of cocoa
butter equivalents from prickly-pear juice fermentation by an
unsaturated fatty acid auxotroph of Cryptococcus curvatus grown in
batch culture” J. PROCESS BIOCHEM, 30(7): 629-634, 1995.
[7] Zzaman, W., U. Issara, , N. F. Febrianto, and T. A., Yang, “Fatty
acid composition, rheological properties and crystal formation of
rambutan fat and cocoa butter” INT FOOD RES J, 21(3): 983-987,
2014.
[8] Lipp, M., E., Anklam, “Review of cocoa butter and alternative fats
for use in Chocolate Part A. Compositional data” FOOM CHEM,
62:73–97, 1998.
[9] Febrianto, N. A., “Effect of Fermentation and Roasting Treatment on
Fat of Rambutan (Nephelium lappaceum L.) Seed and Its Potential
Utilization as Confectionery Fat”, M.Sc. Thesis. Universiti Sains
Malaysia. Penang, Malaysia, 2013.
[10] Lannes, S.C.S., M.L., Medeiros, and L.A., Gioielli, “Physical
interactions between cupuassu and cocoa fats” Grasas y Aceites, 54:
253–258, 2003.
[11] Asmaa, A. A., W. Zzaman, and A. Y. Tajul, “Effect of superheated
steam cooking on fat and fatty acid composition of chicken sausage”
INT FOOD RES J, 22(2): 598-605, 2015.
[12] AOAC, “Association of Official Analytical Chemists” 15th Ed.;
Arlington, 15/e, Gaithersburg, 1995.
[13] Lawless, H.T. and H. C. Heymann, “Sensory evaluation of food
principles and practices”, 2th ed. Heidelberg: Springer-Verlag Berrlin.
P. 8-75, 2010.
[14] Zzaman, W., R. Bhat, and T.A. Yang, ʻʻEffect of Superheated
Steam Roasting on the Phenolic Antioxidant Properties of Cocoa
Beansʼʼ, J FOOD PROCESS PRES, 38 (4): p. 1932-1938, 2014.
[15] Narine, S.S., A.G. Marangoni, “Fat Crystal Networks”, Marcel
Dekker, New York, p. 179-255, 2005
[16] Lannes, S.C.S., M.L. Medeiros, and L.A. Gioielli, “Physical
interactions between cupuassu and cocoa fats”, Grasasy Aceites, 55:
115–121, 2004.
[17] Lannes, S.C.S. and L.A. Gioielli, “Misturas entre manteiga de cacau
e sucedaneoscomerciais: estudo de diagramas de curvasiso-solidas e
de iso-consistencia” REV SOC BRAS, 15:132-7, 1997.
[18] Zee, F., Rambutan and pili nuts: potential crops for Hawai. In: Janick,
J., Simon, J.E. (Eds.), New Crops, p. 461–465. Wiley and Sons Inc.,
New York, 1993.
[19] Solís-Fuentes, J.A., et al., “Composition, phase behavior and thermal
stability of natural edible fat from rambutan (Nephelium lappaceum
L.) seed” BIORES TECHNOL, 101: 799-803, 2010.
[20] Sirisompong, W., W. Jirapakkul, and U. Klinkesorn, “Response
surface optimization and characteristics of rambutan (Nephelium
lappaceum L.) kernel fat by hexane extraction” LWT-FOOD SCI
TECHNOL, 44: 1946-1951, 2011.
[21] Teng, Y., Y. Xu, and D. Wang, “Production and regulation of
different lipase activities from Rhizopus chinensis in submerged
fermentation by lipids” Jiangnan University, PR China: State Key
Laboratory of Food Science and Technology. thermal treatment of
refined and unrefined vegetableedible oils. Czech J. Food Sci., 28:
376–384, 2008.
[22] Sudaryatiningsih, C., and Supyani, “Linoleic and linolenic acid
analysis of soybean tofu with Rhizopus oryzae and Rhizopus
oligosporus as coagulant” BIOSCI, 1: 110–116, 2009.
[23] Zaidul, I.S.M., N.A. Norulaini, A.K. Mohd Omar, and R.I. Smith,
“Blending of suprecritical carbon dioxide (SC-CO2) extracted palm
kernel oil fractions and palm oil to obtain cocoa butter replacers” J
FOOD ENG, 78:1397-1409, 2007.
[24] Manaf, Y. N. A., etal., “Physico-chemical characterization of the fat
from red-skin rambutan (Nephellium lappaceum L.) seed” J OLEO
SCI, 62(6), 335-343, 2013.
[25] Chaiseri, S., P.S. Dimick, “Lipid and hardness characteristics of
cocoa butters from different geographic regions” J AM OIL CHEM
SOC, 66: 1771–1776, 1989.
[26] Rajko, V., V. Sergeja, and A. Helena, “Biochemical parameters and
oxidative resistance to thermal treatment of refined and unrefined
vegetableedible oils”, CZECH J Food SCI, 28: 376–384, 2010.
62
... In both cases, the presence of fruit pulp that surrounds the rambutan seed or cocoa bean seed supplies the sugars needed for natural fermentation to take place. Fermentation of rambutan seed alone with very little or without the pulp has been reported by Febrianto, Yang, and Wan Abdullah (2016), Febrianto, Issara, Yang, andWan Abdullah (2014), Luma Khairy, Saadoon, Varastegani, Yang, andZzaman (2017) and Mehdizadeh, Lasekan, Muhammad and Baharin (2015). ...
... Blending the rambutan seed fat with a softer oil or harder fat may lead to products with wider usage. A few groups of researchers showed that the physicochemical properties of the fat from either non-fermented (Chai, Adzahan, Karim, Rukayadi, & Ghazali, 2018;Issara, Zzaman, & Yang, 2014;Luma Khairy, Yang, & Fered, 2015;Manaf et al., 2013) or fermented rambutan seeds (Febrianto et al., 2016;Febrianto et al., 2014;Luma Khairy et al., 2017;Mehdizadeh et al., 2015) allow it to be a cocoa butter alternative. Hence, it is possible to ferment the whole rambutan fruit and obtain the seed fat, similar to that of cocoa butter, as fermentation has been shown to bring about positive effects on the physicochemical properties of a food product . ...
... Similar observations were reported by Achinewhu (1986) who found that the total unsaturated fatty acid of oil bean seeds increased while its total saturated fatty acid decreased by 5% after four days of fermentation. Fermentation microorganisms, namely yeasts, lactic acid bacteria and acetic acid bacteria (Mehdizadeh et al., 2015), probably utilized the lipids as a carbon or energy source and also support their cell wall phospholipid development (Luma Khairy et al., 2017) and thus, the fatty acid composition of the seed fat is altered. Fig. 1 shows the TAG profile of rambutan seed fat after 0, 1, 3, 5, 7 and 10 days of fermentation. ...
Article
Rambutan seed is usually discarded during fruit processing. However, the seed contains a considerable amount of crude fat. Hence, the objective of this study was to investigate the fat properties and antinutrient content of the seed during fermentation of rambutan fruit. Results showed that the crude fat content of the seed reduced by 22% while its free fatty acid content increased by 4.3 folds after 10 days of fermentation. Arachidic acid was selectively reduced and was replaced by linoleic acid from the seventh day of fermentation onwards. Only 14.5% of triacylglycerol remained in the seed fat at the end of fermentation. The complete melting temperature, crystallization onset temperature and solid fat index at 37 °C of the fermented seed fat were higher than that of non-fermented seed fat. The saponin and tannin contents of the seed were reduced by 67% and 47%, respectively, after fermentation.
... Moringa oleifera extracts are one of the most important natural alternatives to chemical antioxidants, which pose a health risk due to their cumulative effect [6]. Moringa oleifera seed oil is one of the most important natural alternatives as it contains tocopherol, phenols, carotenoids and sterols [7][8][9]. In addition to the high content of oleic acid, this is important for extending the shelf life of oils and increasing their stability [8,10]. ...
Article
Full-text available
The study aimed to extend the shelf life of flaxseed oil, which is rich in essential polyunsaturated fatty acids, especially omega-3 fatty acids, by adding different proportions (0.5%, 1%, 2%) of Moringa Oleifera seed oil to the treatments (T 2 , T 3 , T 4 ) successively to flaxseed oil and comparing the results with flaxseed oil without additives (T 0 ) and flaxseed oil added 200ppm of the synthetic antioxidant (BHT) for treatment (T 1 ). The addition led to shelf life extension to (45, 50, 55) days for treatments (T 1 , T 2 , T 3 ) respectively, while the shelf life of flaxseed oil (T 0 ) did not exceed 40 days, considering vegetable oils acceptable and within the approved standard specifications for edible oils (free fatty acids not exceeding 2%, peroxide values not exceeding 10 meq.O 2 / kg oil, and thiobarbituric acid value not exceeding 3). The results showed that the highest storage period was achieved with the addition of 2 %Moringa oleifera (T 4 ) seed oil, with results for (FFA=1.6) and (P.V=9) and (TBA=1.9) for a storage period of over 60 days at room temperature (25±2) °C, as Moringa Oleifera seed oil is characterized by a high percentage of active antioxidant compounds(phenols, sterols, tocopherols and, carotenoids) reached (119, 1700, 88,17) ppm respectively, and high percentage of oleic acid which reached abut72.38% that makes it more resistant to oxidation compared with other unsaturated fatty acids. at the same time flax seed oil contained 51.146% linolenic acid, which is characterized by its rapid oxidation and needs antioxidant to extend shelf life.
... A plausible explanation for the change in the fatty acid profile relates to the preference of some saturated fatty acids for the fermenting microorganisms as energy sources. From a different point of view, Luma Khairy et al. (2017) attributed the altered fatty acid composition in the seeds after fermentation to the use of some specific fatty acids to the development of their plant cell wall phospholipid development [28]. In addition, Dos Santos-Oliveira et al. (2011) identified a similar change in the fatty acid profile after fermenting rice bran with Rhizopus oryzae, accounting for decreased saturated and 5% increased unsaturated fatty acids, and a concomitant increase of phospholipids and decreased triglycerides [29]. ...
Article
Full-text available
Fermentation of plant-based substrates with edible fungi enhances the nutrient profile and digestibility, but it has been scarcely applied to edible seeds, which are rich in healthy lipids. In this study, chia and sesame seeds were solid-state fermented with Pleurotus ostreatus, followed by drying and milling. Fermentation led to increased content of lipid and protein in both seeds’ products, and a change in fatty acid profile in favor of increased polyunsaturated fatty acids. Then, the samples were subjected to in vitro digestion. Lipolysis, determined by nuclear magnetic resonance, was higher in sesame than in chia products, and the fermented counterparts had increased values compared to the controls. In terms of physical properties, fermentation showed reduced particle size and increased matrix degradation and decreased viscosity of the digestion medium, which were related to increased lipolysis. In conclusion, applying solid-state fermentation on chia and sesame seeds could be a recommendable approach.
... Other than having this high vaue nutritional content, previous studies has stated that rambutan seed is potential to be used in food application. Rambutan can be as cocoa butter substitute [16][17][18] has been tested as a low-calorie thickener for replacement of egg yolk or vegetable oil in the formulation of 'Thousand Island Dressing' [19]. However, there has not been a study to incorporate rambutan seed flour into pastry product, especially biscotti. ...
Article
Full-text available
Biscotti is small rectangular bar biscuits containing nuts, twice-baked, oblong-shaped, dry, crunchy, and made from flour, sugar, eggs, pine nuts and almonds. Generally, the flour used is derived from wheat. However, the flour can also be made from rambutan seed that have nutritional value which is good for health. The objectives of this study were to: 1) find the best formula from rambutan seed flour biscotti; 2) know the nutritional value of the selected formula; and 3) know the consumer acceptability. This research was experiment with one factor model in different propotional levels (40; 60; 80; 100), and it analyzed using chemical test and descriptive analysis of sensory quality. The nutritional value of biscotti obtained were compared with nutritional value of rambutan seed flour. These include energy, protein, carbohidrates, fat, ash, Vit C, fiber, and antioksidant. The result showed that 1) the best formula on sensory quality of rambutan seed flour biscotti is resulting from more than a half rambutan seed flour subtitutions; 2) the selected formula contain energy, protein, carbohidrates, fat, ash, Vit C, fiber, and antioxidant; and 3) the consumer acceptability of biscottti from the best formula namely: odor, texture, crunchiness, taste and overall acceptability. This study indicate that 60-80 rambutan seed flour can be utilized as potential raw material food for biscotti.
... The sugars, mainly sucrose, fructose, and glucose contained in the rambutan pulp provide nutrients for microorganisms to grow and carry out fermentation (Chai et al., 2018c). Fermentation of rambutan seed alone with very little or without the pulp has been previously reported (Febrianto et al., 2014;2016;Mehdizadeh et al., 2015;Khairy et al., 2017). In cocoa bean processing, the fermentation of beans begins almost immediately and ends by the 5 th or 6 th day. ...
Article
Full-text available
A novel way to reduce rambutan wastage is to ferment the fruit and valorise the seed post-fermentation into other food products and ingredients. Hence, the objective of this study was to investigate the physicochemical properties of rambutan seed during solid-state fermentation of the fruit. Peeled rambutan fruits were subjected to natural fermentation for ten days at 30°C. The environmental temperature, relative humidity, internal and external temperatures of the fermentation mass were measured daily. After ten days of fermentation, the seeds had higher cut test score (867.5), fermentation index (1.527), and a* value (8.20 for non-dried seeds and 9.93 for dried seeds), and lower L* (51.90 for non-dried seeds and 49.22 for dried seeds) and b* (30.52 for non-dried seeds and 30.12 for dried seeds) values; as compared to the non-fermented seeds (cut test score, 0.0; fermentation index, 0.856; L*, a*, and b* values, 64.52, 2.25, and 42.07 for non-dried seeds, respectively, and 61.03, 3.23 and 36.70 for dried seeds, respectively). During this time, pH, total soluble solids, fructose, glucose, sucrose, citric acid, and tartaric acid contents of the seeds decreased by 46, 44, 59, 61, 100, 85, and 100%, respectively , while the titratable acidity, lactic acid, acetic acid, and ascorbic acid contents of the seeds increased by 5.5, 7.8, 6.0, and 2.2-fold, respectively. Results showed that eight days of fermentation are adequate to produce well-fermented rambutan seeds that could be further processed into a cocoa powder-like product by roasting the fermented fruits in a manner similar to that of cocoa bean roasting.
... 11 Recently, many researchers reported that the physicochemical properties of RSF from either fermented or nonfermented rambutan seeds are suitable as cocoa butter alternatives. 3,7,[12][13][14] Chai et al 15 produced a cocoa powder-like product from the roasted seeds of fermented rambutan fruit. Thus, optimising the extraction of fat from rambutan seed is crucial in achieving the highest yield. ...
Article
Full-text available
The pre‐treatment of oilseeds prior to extraction process may affect oil yield and quality. The aim of this study was to investigate the effects of two drying methods on rambutan seed fat (RSF) yield and their oxidative stability, physicochemical properties, and crystal morphology. Response surface methodology (RSM) was used in the optimisation and investigation of the effects of three process conditions: seed weight (g), extraction time (min), and solvent volume (ml) on RSF yield. Under optimal conditions, a maximum RSF yield of 44.14% was obtained. The differences between RSF pre‐treated with oven‐drying and RSF with freeze‐drying methods in slip melting point (38.3°C to 39.7°C), free fatty acid (3.13 to 3.50 mg KOH/g fat), peroxide value (1.04 to 1.67 meq of O2/kg of fat), p‐anisidine value (1.10 to 1.56), and total oxidation value (4.21 to 5.67) were significant (p < 0.05). Both fats showed needle‐like shaped crystals. Our results provide useful information in the pre‐treatment of RSF, which has potential to be used as blending component with palm oil for cocoa butter equivalent formulation in chocolate and confectionery industries.
... However, in the Philippines, roasted seeds are consumed (Solís-Fuentes, Camey-Ortíz, Hernández-Medel, Pérez-Mendoza, & Durán-de-Bazúa, 2010). The studies conducted by Chai, Adzahan, Karim, Rukayadi, and Ghazali (2019a), Febrianto, Issara, Yang, and Abdullah (2014) and Luma Khairy, Saadoon, Varastegani, Yang, and Zzaman (2017) revealed that fermented rambutan seed fat is suitable to be used as a cocoa butter extender. However, to date, there is no report on the effect of turning intervals on the characteristics of fat and the content of anti-nutrient of rambutan seed during the fruit fermentation. ...
Article
The present study investigated the effect of turning intervals on the composition and thermal behavior of rambutan seed fat and anti-nutrient content of the seed during rambutan fruit fermentation. Peeled rambutan fruits were subjected to eight days of fermentation at different turning intervals (no turning, turning at every 24, 48 and 72 h). Results showed that increase of turning frequency did not affect the characteristics of the seed fat, but the contents of tannin and saponin of the seeds reduced significantly (p < 0.05) by 8–36% and 4–37%, respectively. Regardless of turning intervals, after eight days of fermentation, the seeds contained about 32 g/100 g of crude fat with oleic (41.02–42.38%) and linoleic (27.91–33.10%) acids being the major fatty acids. Five unknown TAGs were found in the fermented seed fat and they constituted about 90.67–91.32% to the total of TAG. Results also showed that the seed fat without turning during fermentation had higher crystallization onset and complete crystallization temperatures compared to that of seed fat with turning. In short, turning brought about beneficial effects to the seeds by reducing its anti-nutrient content and subsequently, the fat from the fermented seeds could be used as a cocoa butter extender.
... However, there is always a glut of the fruit during harvest season and much of the fruits are wasted. Studies have shown that fermenting rambutan fruits could transform the fruits into other products and subsequently, reducing wastage (Febrianto et al. 2016(Febrianto et al. , 2014Luma et al. 2017;Mehdizadeh et al. 2015). ...
Article
Full-text available
Sweatings, the exudates that leach out from fermenting fruits during rambutan fruit fermentation are considered as a waste by-product and are allowed to be drained off. This could lead to a pollution problem. Besides, it is a waste if the sweatings are possible to be transformed into food products and ingredients. However, prior transformation, the fundamental knowledge of the sweatings should be understood. Hence, the main aim of this study was to investigate the physicochemical properties of sweatings as affected by fermentation time and turning intervals during natural fermentation of rambutan fruits. In this study, peeled rambutan fruit was fermented for 8 days and turned. Different batches of the fruits were turned either every 24, 48 or 72 hours, and sweatings from the process were collected and analyzed. The results showed that fermentation time significantly reduced (p<0.05) the yield, pH and sucrose content of the sweatings by 79-84 %, 32-33 %, 76.5-80.8 %, respectively. Fermentation time also significantly increased (p<0.05) the titratable acidity, total soluble solids, fructose, glucose, total sugar, citric acid, lactic acid, acetic acid and ascorbic acid contents of the sweatings by 5.6-6.0, 1.5-1.6, 2.4-2.6, 2.1-2.5, 1.0-1.1, 5.7-6.5, 2.4-2.6, 2.1-2.5 and 2.6-2.8 folds, respectively. However, turning intervals did not significantly affect (p>0.05) the physicochemical properties of the sweatings. High concentrations of sugars and organic acids allow the sweatings to have a balance of sweet and sour taste and they are suitable to be used in the production of syrup, soft drinks, jam, jelly, marmalade and vinegar.
Article
Full-text available
This review of literature provides an overview on the compositional data of Rambutan (Nephelium lappaceum Linn.) and rambutan seed fat for usage in chocolate product. It is a seasonal fruit native of west Malaysia and Sumatra. It is harvested when the fruit have reached optimum visual and organoleptic quality. Rambutans rapidly deteriorate unless proper handling techniques are employed. The rambutan fruits are deseeded during processing and these seeds (~ 4-9 g/100 g) are a waste by-product of the canning industry. And some studies was showed that rambutan seed possesses a relatively high amount of fat and these fats are similar to those of cocoa fat, although have some different physical properties. In the present research about rambutan seed fat continued increasing due to from previous research was found that this fat can use as substitute in cocoa butter for chocolate products. Therefore, the extracted fat from rambutan seed not only could be used for manufacturing candles, soaps, and fuels, but it also has a possible to be a source of natural edible fat with feasible industry use.
Article
Full-text available
The influence of superheated steam cooking on fat and fatty acid composition of chicken sausage were investigated at various temperatures (150, 200, and 250°C) with different time domains (2-6 min). It has been found that the fat content of raw sample was higher than that of all cooked samples. The total fat content of cooked sample, showed a linear decreasing with time at all investigated temperatures. Superheated steam produce changes in saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA) in which their values were found to decrease in cooked samples. When different cooking conditions (temperature, time) were applied, the fatty acids were decreased as the time and temperature increased. The PUFA and MUFA were less prone to decrease at 150°C, while at this temperature there was a remarkable loss in SFA content. This cooking method considerably reduced the level of fat and SFA which have a positive effect on health. In addition it could imply a great choice for consumers to choose the healthier technique for cooking food.
Article
Full-text available
In human nutrition fats are physiologically important food constituents but also the components most liable to oxidative degradation. The oils included in the study were refined (sunflower, extra-sunflower, soybean, and rapeseed) as well as unrefined (olive and pumpkin-seed) oils. The aim of our study was to determine the fatty acid composition, tocopherol content, and quality parameters such as the free fatty acid content, peroxide value, and induction time. Extra virgin olive oil had the highest average peroxide value, while unrefined pumpkin seed oil had the lowest one. The acid value of the unrefined oils was higher on average than that of the refined oils. Soybean oil had the highest total tocopherol content and extra virgin olive oil the lowest one. The refined oils with higher contents of saturated and monounsaturated fatty acids and lower polyunsaturated fatty acid contents had a high oxidative stability. A negative correlation has been found in the oils between the induction time and polyunsaturated fatty acid content. Among the oils investigated, unrefined pumpkin seed oil was the most oxidatively stable, the other oils following in the decreasing order: extra virgin olive > high oleic sunflower > rapeseed > soybean > sunflower oil. The oxidative stability of the unrefined oils was better than that of the refined oils.
Article
Full-text available
The study was conducted to investigate fatty acid composition, rheological properties and crystal formation of rambutan fat and cocoa butter. The results showed that lauric acid, palmitic acid, and stearic fatty acid in rambutan fat were less than cocoa butter, but oleic acid found almost the same. The crystal formation of cocoa butter was not complex at 25°C, while rambutan fat and their mixture shown complicated network of crystal form. The Newton, Bingham and Casson plastic rheological models was used to describe fat flow in this experiment and the result showed that rambutan fat had higher viscosity than cocoa fat. Based on the results the study recommended that mixture proportion up to 30% rambutan seed fat can be used as a cocoa butter substitute whereas higher proportion completely alters original cocoa butter properties. Therefore, there is feasibility of using the rambutan fat to substitute cocoa butter and the mixtures of the two fats in suitable proportion in chocolate manufacturing.
Article
Sudaryatiningsih C, Supyani. 2009. Linoleic and linolenic acids analysis of soybean tofu with Rhizopus oryzae and Rhizopus oligosporus as coagulant. Nusantara Bioscience 1: 110-116. The aims of this research are to know the potency of Rhizopus oligosporus and Rhizopus oryzae as a coagulant in tofu processing for increasing the amount of linoleic and linolenic acids, and to know the time that needed by R. oligosporus and R. oryzae for increasing the amount of linoleic and linolenic acids. It uses PDA for inoculating fungi, and it is done at Sub-Lab Chemistry, Central Laboratory for Mathematics and Natural Sciences, Sebelas Maret University, Surakarta. The tofu making was done in “Dele Emas” Tofu Factory, Surakarta. Analysis of linoleic and linolenic acids was done by Gas Chromatography, in LPPT-UGM Yogyakarta. The conclusion of this research is R. oligosporus dan R. oryzae having a potency as a coagulant in tofu processing for increasing the amount of linoleic and linolenic acids. R. oryzae needs 18 hours to coagulate the tofu, and R. oligosporus requires 12 hours for the same process. R. oryzae obtained the highest amount of linoleic and linolenic acids. R. oryzae at 6 hours of fermentation (0.26% and 0.14%), and 24 hours of fermentation by R. oligosporus (0.06% and 0.04%).
Article
Cocoa beans (Theobroma cacao) are rich in phenolic compounds that show antioxidant properties. Roasting is one of the most important unit operations in the cocoa-based industries which reduces the antioxidant properties. Cocoa beans were subjected to roast at 150, 200 and 250C for 10–50 min using superheated steam method. The effect of roasting temperature and times on the total phenol content (TPC), total flavonoid content (TFC) and antioxidant properties was investigated. The TPC and TFC were evaluated using gallic acid and epicatechin, respectively. The free radical scavenging activity was measured using 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay and antioxidant properties were evaluated using ferric reducing antioxidant power assay. The total phenols and total flavonoids decreased significantly (P < 0.05) with increasing time and temperature. The cocoa beans showed significantly (P < 0.05) lower free radical scavenging activity and antioxidant properties at higher temperature and time.Practical ApplicationsThe chocolate industry is global and economically important worldwide. The main raw material of chocolate is cocoa beans. The introduction of a new method for roasting cocoa beans may interest cocoa production industries that may be beneficial to consumers as well as to industry. Effective roasting of cocoa beans using superheated steam considerably brings about lucrative prospects in cocoa product manufacturing. As a new method for food processing, superheated steam roasting is more convenient and flexible than conventional method because the higher total phenol and antioxidant properties are preserved. At the same time, the favorable characteristics of food in terms of antioxidant properties are maintained.